High pressure variable vane pump with vane pins

ABSTRACT

A vane pump has a rotor and a control slide mounted within an internal chamber of a housing. The rotor has a number of vane mounting openings and vanes. Rotation of the rotor generates a pressure differential between inlet and outlet ports of the pump to draw fluid in and output the fluid out. Both the vane mounting openings and vanes are arranged in pairs that are diametrically opposed to one another with respect to the rotor axis. The vanes in each said pair have an intermediate transfer member extending therebetween that shifts with one vane of each said pair retracting radially inwardly by engagement with the internal surface of the rotor receiving space for extension of the opposing vane of each said pair radially outwardly toward the internal surface of the rotor receiving space. The intermediate transfer member may be a pin provided between the vanes of the pair.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent Application No. 63/287,376, filed Dec. 8, 2021, the entire contents of which are herein incorporated by reference in its entirety.

BACKGROUND Field

The present disclosure is generally related to a variable vane pump.

Description of Related Art

Vane pumps are well known for various applications, including but not limited to automotive applications, and specifically oil pumps. The typical vane pump design includes a rotor with a plurality of vanes individually mounted to slots on the rotor. The rotor resides in a control slide, and as the rotor rotates the vanes are moved along the internal surface of the control slide. The pressure and displacement of the pump may be varied by altering the eccentricity of the control slide relative to the axis of the rotor. The control slide is pivoted about a control axis to alter the eccentricity, and may be moved linearly as well. The change in eccentricity affects the pressure differential generated by the rotation of the vanes within the control slide.

When eccentricity is increased, the vanes moving through the suction or low pressure side of the pump are extended, while the vanes are retracted as they move through the ejection or high pressure side of the pump where the fluid is output through an outlet. As such, the fluid drawn into the low pressure side of the pump from the inlet is pressurized to a greater extent as the vanes are moved through the high pressure side because the volume between each vane pair is reduced, i.e., the higher eccentricity creates a higher pressure differential between low and high pressure sides and hence between the inlet and the outlet. In contrast, when the eccentricity is decreased, the vanes moving through the low pressure side are less extended and the vanes on the high pressure side are less retracted, and thus less pressure differential is generated. Many vane pumps have a pressure feedback to decrease eccentricity in response to the output pressure increasing for maintaining a relatively stable pressure. Some vane pumps have controls for establishing different pressure set points as well, including by actively controlling pressure application to decrease or increase eccentricity.

Another approach is to feed/relieve pressurized fluid to and from the vane slots to provide pressure for extending the vanes when on the low pressure side of the pump and relieve the pressure for retracting them when on the high pressure side of the pump. Examples of this approach is found, for example, in U.S. Pat. Nos. 6,655,936, 7,841,846, and 7,993,116 and U.S. Patent Publication No. 2012/0045355, each of which is incorporated herein in their entirety. CN202833142U shows a more complicated approach where auxiliary vanes associated with each vane are also moved by fluid pressure. These approaches can require complicated porting that increases the overall volume of the pump (or makes less volume available for displacement for a pump of the same size and design), and also can reduce the pump efficiency because a portion of the pressurized fluid is diverted for purposes of use for vane extension.

SUMMARY

It is an aspect of this disclosure to provide a vane pump that includes: a housing having an internal chamber; an inlet port; an outlet port; a rotor rotatably mounted in the internal chamber for rotation about a rotor axis, and a control slide mounted in said internal chamber. The rotor has a plurality of vane mounting openings and a plurality of vanes mounted in and extending radially from the vane mounting openings, and the vanes are slidable radially in the vane mounting openings. The control slide has an internal surface defining a rotor receiving space. The rotor receiving space is in communication with the inlet and outlet ports and the rotor is received in the rotor receiving space with the vanes slidably engaging the internal surface of the control slide such that rotating the rotor generates a pressure differential between the inlet and outlet ports to draw fluid in through the inlet port and output the fluid out through the outlet port. The vane mounting openings are arranged in pairs of vane mounting openings that are diametrically opposed to one another with respect to the rotor axis and wherein the plurality of vanes include pairs of vanes that are diametrically opposed to one another with respect to the rotor axis. The vanes in each said pair have an intermediate transfer member extending therebetween that shifts with one vane of each said pair retracting radially inwardly by engagement with the internal surface of the rotor receiving space for extension of the opposing vane of each said pair radially outwardly toward the internal surface of the rotor receiving space.

Other aspects, features, and advantages of the present disclosure will become apparent from the following detailed description, the accompanying drawings, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic, top view of features in a variable vane pump, with a cover removed, in accordance with an embodiment of the disclosure.

FIG. 2 illustrates a vane pressure inlet port and a vane pressure outlet port in a porting plate of the vane pump of FIG. 1 .

FIG. 3 shows a cross sectional view through the control slide, vanes, porting plate, and ports of the vane pump of FIG. 1 , in accordance with an embodiment.

FIG. 4 illustrates an isometric view of the features of the vane pump of FIG. 1 .

FIG. 5 illustrates an underside view of features of the vane pump of FIG. 1 in accordance with an embodiment.

FIG. 6 illustrates a top view of a rotor of the vane pump in accordance with an embodiment.

FIG. 7 illustrates a side view of the rotor of FIG. 6 and drive shaft in accordance with an embodiment.

FIG. 8 is a cross-sectional view taken along line 8-8 of FIG. 7 .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

The description set forth below in connection with the appended drawings is intended as a description of various embodiments of the disclosed subject matter and is not necessarily intended to represent the only embodiment(s). In certain instances, the description includes specific details for the purpose of providing an understanding of the disclosed embodiment(s). However, it will be apparent to those skilled in the art that the disclosed embodiment(s) may be practiced without those specific details. In some instances, well-known structures and components may be shown in block diagram form in order to avoid obscuring the concepts of the disclosed subject matter.

Reference throughout the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification is not necessarily referring to the same embodiment. Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments. Further, it is intended that embodiments of the disclosed subject matter cover modifications and variations thereof.

It is to be understood that terms such as “top,” “bottom,” “side,” “upper,” “lower,” “interior,” “exterior,” “inner,” “outer,” and the like that may be used herein merely describe points of reference and do not necessarily limit embodiments of the present disclosure to any particular orientation or configuration. Furthermore, terms such as “first,” “second,” etc., merely identify one of a number of portions, components, steps, operations, functions, and/or points of reference as disclosed herein, and likewise do not necessarily limit embodiments of the present disclosure to any particular configuration or orientation, or any requirement that each number must be included.

As understood by one of ordinary skill in the art, “pump displacement” or “displacement” as used throughout this disclosure refers to a volume of liquid or fluid (e.g., lubricant, oil) a pump is capable of moving during a specified period of time, i.e., a flow rate.

FIGS. 1-5 illustrate parts of a vane pump, also referred to as a variable vane pump in the art and in some cases just as a “pump” throughout this disclosure. The disclosed vane pump may be a pivoting vane pump, a sliding vane pump, or a fixed vane pump. The vane pump has a control slide within its housing and may have at least one control chamber in the housing for receiving pressurized fluid. Vanes are arranged and connected in pairs and are received in a rotor that rotates within and relative to the control slide. The vanes of each pair are designed to move relatively together and, as detailed below, limited in movement towards a center of the rotor.

FIG. 1 shows a top or overhead view of the pump, in accordance with an embodiment, with its cover removed. The pump is a variable displacement vane pump for dispensing fluid or fluid to a system, in accordance with an embodiment. The housing 17 has an inlet and an outlet, and an internal chamber 21. The inlet receives fluid or inputs fluid (typically oil in the automotive context) to be pressurized or pumped from a source into the housing 17, such that the fluid is pressurized therein, and the outlet is used for discharging or delivering the pressurized fluid or lubricant to the system, e.g., engine or transmission, from the housing 17 and/or a sump for holding fluid. A control slide 6 (explained in greater detail below), a rotor 1, and an optional resilient structure 20 are provided in housing 17, as is generally known in the art.

The inlet and outlet are disposed on opposing radial sides of a rotational axis A-A of the rotor 1 (described later). As seen in FIGS. 1 and 5 , the housing 17 has at least one inlet port 12 that defines the inlet for intaking fluid to be pumped, and at least one outlet port 13 that defines the outlet for discharging the fluid. The inlet port 12 and outlet port 13 each may have a crescent shape, in accordance with one embodiment; however, the shape as shown in the Figures is not intended to be limiting. The inlet port 12 and outlet port 13 may be formed through a same wall located on one axial side or both axial sides of the housing (with regard to the rotational axis of the rotor 1). In an embodiment, the inlet and outlet ports 12, 13 may also be disposed on opposing radial sides of the rotational axis of the rotor 1. These structures are conventional, and need not be described in detail. The shape of the inlet and/or outlet is also not intended to be limiting. Other configurations may be used, such as differently shaped or numbered ports, etc. Further, it should be understood that more than one inlet or outlet may be provided (e.g., via multiple ports). As described below, in an embodiment, further ports 14, 15 may be provided in the vane pump.

The housing 17 may be made of any material, and may be formed by aluminum die cast, iron sand cast, powdered metal forming, forging, or any other desired manufacturing technique. The housing 17 encloses an internal chamber, which includes a control chamber 9 (described later). In the drawings, the main shell of the housing 17 is shown. Walls define axial sides of the internal chamber and a peripheral wall having an inner surface extends substantially around to define and surround the internal chamber peripherally. A cover (not shown) attaches to the housing 17, such as by fasteners (e.g., bolts) that are inserted into various fastener bores placed along or around the housing 20. The cover is not shown in the Figures so that internal components of the pump can be seen. However, use of such cover and fasteners is generally well known and need not be described in greater detail here throughout. The cover may be made of any material, and may be formed by stamping (e.g., stamping steel or another metal), aluminum die casting, iron sand casting, powdered metal forming, forging, or any other desired manufacturing technique. A gasket or other seal(s) may optionally be provided between the cover and peripheral wall of the housing to seal the internal chamber. Additional fastener bores for receipt of fasteners may be provided along the peripheral wall of the pump, to secure or fix the pump to an engine, for example. The housing 17 and cover includes various surfaces for accommodating movement and sealing engagement of the control slide 6 therein.

As mentioned, a control slide 6 is mounted in the internal chamber of the vane pump. In one embodiment, the control slide 6 may be provided in the pump in a fixed slide position. In another embodiment, a resilient structure 20 may optionally be used to bias the control slide 6 in one direction. That is, in an embodiment, the control slide 6 (also known as a “control ring” or a “cam ring” in the art in some instances) may be displaceable within the housing 17 and relative to the cover between at least a first slide position and a second slide position (or in between the two positions, and, in some cases, a third slide position or any number of positions), to adjust displacement of the pump and thus flow through the outlet (e.g., as fed through the outlet port 13). In accordance with an embodiment, the control slide 6 is pivotally mounted and configured for pivotal displacement within the housing 17 between at least the first and second slide positions. For example, the control slide 6 can be pivotally mounted relative to the internal chamber. When the control slide 6 is displaced away from the first slide position, the control slide 6 can be considered to be in a second slide position, despite the angle of pivoting or rotation. In an embodiment, the control slide 6 is displaceable within the internal chamber of the housing in a displacement increasing direction for increasing pump displacement and a displacement decreasing direction for reducing pump displacement.

In one embodiment, the pump has a control chamber 9 (further described below) between the housing 17 and the control slide 6 for receiving pressurized fluid to move the control slide 6 from an increased displacement direction into a displacement decreasing direction. In the illustrated embodiment, pressure in the control chamber 9 acts in the opposite decreasing direction compared to the resilient structure 20, which acts in the displacement increasing direction. In one embodiment, the first slide position is defined as a home position, which may provide maximum displacement by the pump, i.e., a position or direction that increases eccentricity between the control slide 6 and rotor axes. As the eccentricity increases, the flow rate or displacement of the pump increases. Conversely, as the eccentricity decreases, and the control slide 6 pivots away from the first position to a second/displacement decreasing position, so the flow rate or displacement of the pump also drops or decreases. More particularly, pressure from the outlet of the pump may be fed into control chamber 9 so that when fluid pressure rises in the outlet, so does the pressure in control chamber 9, thereby moving the control slide 6 to decrease eccentricity and lower the pump pressure (e.g., to remain near a desired target output pressure). Accordingly, the second slide position is different than the first slide position and may be defined as a position away from the first slide position (or away from a position for maximum displacement), e.g., a reduced displacement position. More specifically, in an embodiment, the second slide position may include any number of positions that is away from the first slide position, and may, in one embodiment, include when the slide is close to a minimum displacement position, or may be the minimum displacement position. In some embodiments, there may be a position where the eccentricity is zero, meaning the rotor and slide axes are coaxial. In this position, the flow is zero, or very close to zero, because the high and low pressure sides have the same relative volumes. Again, this functionality of a vane pump is well known, and need not be described in further detail.

In an embodiment wherein the control slide 6 pivots, a pivot pin 18 or similar pivoting or rotation feature may be provided for the pivoting action of the control slide 6, such that the control slide 6 is pivotally or rotationally displaceable about the pivot pin 18 within the internal chamber of the housing 17 between slide positions, as described above. The pivot pin 18 can be mounted to the housing 17. In one embodiment, as shown, the pivot pin 18 is mounted to the housing 17 within the chamber, and the control slide 6 has a concave, semi-circular bearing surface that rides against the pivot pin 18. In some embodiments, the pivot pin 18 may extend through a bore in the control slide 6, rather than within a concave external bearing recess. The configuration of the pivotal connection of the control slide 6 in the housing 17 may have other configurations, and thus these examples should not be considered limiting. In an embodiment, the pivot pin 18 may be mounted in the housing 17 in a position that is adjacent to the outlet. In an embodiment, the pivot pin 18 may be provided in the housing 20 on an opposite side of the inlet.

The control slide 6 has an internal surface defining a rotor receiving space, or pocket. The rotor receiving space may have a configuration or shape that compliments the design, configuration, or shape of a drive shaft and a rotor 1. The rotor receiving space is in communication with the inlet and outlet ports 12 and 13. In an embodiment, this rotor receiving space communicates directly with the inlet and outlet for drawing in oil, lubricant, or another fluid under negative intake pressure through the inlet, and expelling the same under positive discharge pressure out the outlet. In an embodiment, the rotor receiving space is defined by an inner surface of the control slide 6. The inner surface of the control slide 6 defines a working chamber 5, which is also part of the rotor receiving space, and includes a first grooved portion 7 (or slide inlet port) and a second grooved portion 8 (or slide outlet port). The first grooved portion 7 and second grooved portion 8 are provided as indentations (e.g., formed with rounded edges or corners) within the inner surface of the control slide for receiving fluid relative to the working chamber 5. Said grooved portions 7 and 8 are optionally provided in order to work in conjunction with and obtain more control over the timing of the opening and closing of the inlet and outlet ports 12 and 13. For example, the second grooved portion 8 is generally opened for receipt of fluid before the outlet port 13 because it has a smaller cross sectional area than the outlet port 13, so fluid received in the second grooved portion 8 delivers fluid in smoother fashion, for example, through the outlet port 13. In a similar manner, inclusion of first grooved portion 7 allows for smoother fluid flow into the working chamber from fluid flowing into inlet port 12. In an embodiment, the slide grooved portions 7, 8 may be disposed on opposing radial sides of the rotational axis of the rotor 1. Further, in an embodiment, placement of the grooved portions 7, 8 may be determined based on placement of the inlet and outlet ports 12, 13. In one embodiment, the slide grooved portions 7, 8 are positioned adjacent to the inlet and outlet ports 12, 13.

The rotor 1 is received in the rotor receiving space of the control slide 6 and thus rotatably mounted in the internal chamber of the housing 17 for rotation about a rotor axis A-A (see, e.g., FIGS. 2 and 3 ). The rotor 1 is configured for rotation within and relative to the control slide 6 as well for pressuring fluid/lubricant that is input via through inlet port 12. The rotor 1 has a central axis that is typically eccentric to a central axis of the control slide 6. The rotor 1 is connected to a drive input in a conventional manner, such as via a drive pulley, drive shaft, engine crank, or gear (with a drive shaft).

The rotor 1 has a number of vane mounting openings 22 (or slots, or vane slots) and a number of vanes 2 mounted in and extending radially from the vane mounting openings 22. The vanes 2 have a proximal end positioned closer to the center of the rotor and a distal end extending towards and positioned closer to the rotor receiving space/control slide 6. The vanes 2 are slidable radially in the vane mounting openings 22 such that the distal ends of the vanes 2 are configured to slidably engage the internal surface of the control slide 6 during rotation of the rotor 1. Rotating the rotor 1 generates a pressure differential between the inlet and outlet ports 12 and 13 to draw fluid in through the inlet and inlet port 12 by negative intake pressure into the working chamber 5 and output the fluid out from the working chamber 5 through the outlet port 13 and outlet by positive discharge pressure. One or more vanes 2 are moved radially outwardly to engage and/or maintain engagement between distal end(s) of the vane(s) and an inside or inner surface of the rotor receiving space/control slide 6 during rotation of the rotor 1. Further, as the rotor 1 continues to rotate, the pair(s) of vane(s) 2 are moved within their vane mounting opening(s) 22 as the distal end of the extending vane(s) contact the inner surface of the slide 6. The control slide 6 can be moved (e.g., pivoted) to alter the position and motion of rotor 1 and its vane(s) 2 relative to the inner surface of the slide 6, and, thus, alter the displacement of the pump and distribution of fluid through the outlet.

One or more seals may be provided in the vane pump. In FIG. 1 , seal 10 is provided in a portion of the control slide 6 in order to seal control chamber 9. That is, control chamber 9 is defined between the pivot pin 18 and the seal 10 and between an internal wall of the housing 17 and an exterior wall of the control slide 6. Control chamber 9 receives pressurized fluid (e.g., from a pressurized source, such as the outlet path) in the vane pump.

As seen in FIG. 1 , for example, a first circumferential portion of the control chamber 9 is provided in the housing such that it extends on one side of the control slide 6. In an embodiment, a second circumferential portion is provided in the housing on the other, opposite/second side of the slide 6. This second circumferential portion may be connected to and part of an inlet path for the fluid from inlet port 12. As previously described (and noted below), the outlet port 13 may be associated with the control chamber 9 so as to communicate fluid pressure for optionally or selectively moving the control slide 6 (e.g., so that as outlet pressure increases, the slide 6 is moved to decrease eccentricity).

In accordance with an embodiment, the control slide 6 is movable in (a) a displacement increasing direction to increase an eccentricity between the rotor axis A-A and the rotor receiving space for increasing the pressure differential between the inlet and the outlet, and (b) a displacement decreasing direction to decrease the eccentricity between the rotor axis A-A and the rotor receiving space for decreasing the pressure differential between the inlet and the outlet. Because of the eccentric relationship between the control slide 6 and the rotor 1, a high pressure volume of the fluid is created on the side where the outlet is located, and a low pressure volume of the fluid is created on the side where the inlet is located (which in the art are referred to as the high pressure and low pressure sides of the pump). Hence, this causes the intake of the fluid through the inlet and the discharge of the fluid through the outlet. The control chamber 9 is controlled in a traditional manner using passive control, e.g., it is outlet pressure controlled or gallery pressure controlled by pressure feedback. That is, a positive pressure of force from the pressurized fluid can be applied to the control chamber 9, and thus applied to control slide 6, to force the slide 6 into its displacement decreasing direction (i.e., second slide position) where eccentricity is decreased. For this reason, then, control chamber 9 may be also referred to as a pressure regulating or feedback control chamber that receives pressurized fluid and that is configured and arranged to move the control slide 6 in the displacement decreasing direction. In an embodiment, any pressure change in control chamber 9 may result in the control slide 6 moving or pivoting (e.g., centering) relative to the rotor 1, in order to adjust (reduce or increase) displacement in the pump. This functionality of the pump is well known, and need not be detailed further.

Also, in accordance with an embodiment, a drive shaft 25 may be connected to and/or integrally formed with the rotor 1 (i.e., as a one-piece structure, such as seen in the cross-sectional view of FIG. 8 ) for rotating the rotor 1 to cause the vanes 2 to relatively move and to draw fluid in from the inlet and pressurize the fluid for expelling out through the outlet. As understood by those having skill in the art, the drive shaft 25 portion of the rotor 1 is configured to be driven by a driver (not shown) such that it rotates about or around an axis to drive the vane pump. Such a driver may include a drive pulley, drive shaft, engine crank, gear, or electric motor, for example. The drive shaft 25 may extend through parts of the housing 17 (e.g., porting plate 11, described later) and into the internal receiving space of the control slide 6. The drive shaft 25 may also connect to or extend at least partially into a portion of the cover. The drive shaft 25 may be hollow or solid. In the exemplary illustrative embodiment, e.g., in FIG. 1 , the rotor 1 and thus the shaft 25 is shown as being hollow with a central opening 23 therein, in order to illustrate the placement of the intermediate transfer members 3 through said shaft. That is, whether hollow or solid, the rotor drive shaft 25 may be designed with openings or holes therethrough, that the intermediate transfer members 3 are designed to pass through a center of the rotor 1 and allow opposing ends of each transfer member 3 to be positioned relative to each vane pair. As noted later below, the rotor (and thus its drive shaft) may include a central opening 23 and receiving bores 24 therethrough for the intermediate transfer members 3.

In an embodiment where a hollow drive shaft is used, any fluid that accumulates during rotation may be vented through the central opening 23. That is, one end of the shaft may be a closed bore and the other end may be open to vent any fluid that accumulates. Further, use of a hollow drive shaft provides less surface area and weight to the rotor itself. Limiting the surface area for the receiving bores 24 may allow for less drag on the intermediate transfer members 3 as they move or pass through the bores (e.g., during rotation and movement of the vanes).

Typically, the resilient structure 20 may bias or urge the control slide 6 in or towards its displacement increasing direction, or first slide position, in accordance with an embodiment. In the illustrated embodiment, the resilient structure 20 is a spring, such as a coil spring. In accordance with an embodiment, the resilient structure 20 is a biasing member for biasing and/or returning the control slide 6 to its default or biased position (i.e., in a displacement increasing direction, or first or home slide position, e.g., for maximum eccentricity with the rotor 1). In an embodiment, the resilient structure 20 may be provided on a first side of the control slide 12 and the pivot pin 18 may be provided on a second side of the control slide such that it is opposite to that of the resilient structure 20. In one embodiment, the resilient structure 20 may be provided on the first radial side of the rotor 1 and the pivot pin 18 may be provided on the second radial side of the rotor 1.

The positions of the control slide 6 in the disclosed vane pump may be controlled by a main control valve and/or any number of pilot valves which may be configured and arranged to control the pressure in the control chamber 9 behind the slide 6 and, as a consequence, influence the slide position and the pump displacement. Generally, use of such a main control or electrical (PWM) valve with pumps is generally known in the art, and thus not explained in detail herein.

Referring now back to the rotor 1, the number of vane mounting openings 22 are arranged in pairs that are diametrically opposed to one another with respect to the rotor axis A-A, in accordance with an embodiment. Further, the number of vanes 2 include pairs of vanes that are diametrically opposed to one another with respect to the rotor axis A-A. In particular, in accordance with one embodiment, the vanes 2 in each pair are together limited in movement by an intermediate transfer member 3 that shifts with one vane 2 of each pair retracting (slides) radially inwardly by engagement with the internal surface of the rotor receiving space (i.e., control slide 6) for extension of the opposing vane 2 of each pair radially outwardly toward the internal surface of the rotor receiving space. The intermediate transfer member 3 may function for forcibly transfer force from the inwardly moving vane 2 of the pair to the outwardly moving vane 2 of the pair, such that the force applied by the wall that moves retracting vane 2 inwardly is transferred to extend the opposing vane 2 outwardly. In some embodiments, the extending vane 2 may extend outward by its own centrifugal force, such that the transfer member 3 does not need to force its extension. However, the transfer member's shifting will still serve to limit or stop the extending vane 2 from retracting inwardly, such as by force generated against the wall with which it is engaging or resistance/viscosity of the fluid (particular at cold temperatures). That is, the intermediate transfer members 3 may function to limit or stop an extending vanes from moving back inwards, similar to a traditional vane ring, particularly during compression. Proximal ends of one vane of a vane pair may be moved into contact and stopped by the transfer members 3 while the other vanes of the pair has the distal ends moved outwardly towards the rotor receiving space/control slide 6. Each transfer member 3 therefore may be provided for vane support to limit inward movement of a vane, rather than to positively extend the vane itself. However, transfer of force for the positive extension movement is also possible.

Thus, the term intermediate transfer member is thus understood as an intermediate member that applies or transfers force from the retracting vane 2 to cause extension of the opposing vane 2, or it may be a member that transfers position with the retracting vane 2 to be in a position for limiting inward movement of the extending vane 2. Having the intermediate transfer member 3 as s separate member has the advantage of allowing the extending vane 2 to extend separately or ahead of the movement of the transfer member 3.

For convenience, the vane pairs in the illustrated embodiment are the pair at 12 and 6 o'clock, the pair at 2 and 8 o'clock, and the pair at 4 and 10 o'clock, comparing the positions in FIG. 1 to a clock face as an analogy. This clock face analogy is simply used for explanatory purposes, and no particular orientation is required.

In an embodiment, the intermediate transfer member 3 for each pair of vanes 2 is a pin 3 that is provided between the vanes 2 of the pair. The pair of vanes 2 and pin 3 together thus maintain a constant length with regards to movement of the vane pairs, ensuring that extension between vanes is maintained. In one embodiment, each pin 3 is cylindrical. However, the cylindrical configuration and/or use of a pin as the intermediate transfer member for each pair of vanes is illustrative only and not intended to be limiting. Other transfer members, such as rods, bars, or dowels may be used as intermediate transfer members 3. Further, it is envisioned that different types of intermediate transfer members may be used between different pairs of vanes 2 to limit movement of said vanes with respect to a center of the rotor 1 and also freely move with respect to the rotor and within the bores 24 with a clearance for fluid (e.g., oil). The transfer members 3 or pin may be made of any material, including, but not limited to, steel, aluminum, and plastic(s). In an embodiment, the material used to form the transfer members 3 may be based on thermal expansion and/or weight.

According to the exemplary illustrated embodiment, the rotor 1 includes a rotor body (including its drive shaft) with a central opening 23 and the vane mounting openings 22 are designed to extend radially inwardly from an outer radial surface of the rotor body. In one embodiment, the rotor body further includes a number of receiving bores 24 (see FIG. 3 , FIGS. 6-8 ) each extending from a respective vane mounting opening 22 to or towards the central opening 23 of the rotor body. The receiving bores 24 are provided for each pair of vane mounting openings 22 that are radially aligned with one another and have the intermediate transfer member 3 for each associated pair of vanes 3 slidably received therein. Specifically, each radially aligned pair of receiving bores 24 is spaced axially with respect to the rotor axis A—A from each other pair of radially aligned pair of receiving bores 24, such that the intermediate transfer members 3 cross over one another in the central opening 23 of the rotor body, as shown in FIGS. 1 and 3 . The vanes 2 have an axial extent (in the rotational axis of the rotor) that is greater than the pins/transfer members 3, preferably essentially the same axial length as the rotor 1, thus allowing normal size vanes to be used with the transfer members 3 extending between each pair at different positions with respect to the rotor axis in the overlapping manner. Thus, the pins 3 extend through the center of the rotor 1 and act on opposing vane sets. According to a non-limiting embodiment, each pin 3 and each receiving bore 24 is cylindrical.

The intermediate transfer members 3 for the vanes 2 are used in place of traditional vane ring(s) to keep the vanes in contact with the control slide or rotor receiving space. One advantage of not using vane rings is that the complete top and bottom axial end surfaces of the rotor 1 are used for sealing the vane space (relative to parts of the housing 17, e.g., with the later described porting plate 11 and the housing 17 and/or its cover) without a vane ring therebetween, i.e., there is greater sealing and reduced chances of leakage without a vane ring, thus improving volumetric efficiency at high pressure. Further, as explained below, extra volume from an effective internal pump formed behind the vanes (i.e., at or near their proximal ends) may also add to the potential fluid flow and thus increase a total displacement of the pump.

Additionally, as seen in FIGS. 2, 3, and 5 , the vane pump may include a vane pressure inlet port 14 and a vane pressure outlet port 15. Each of these ports 14, 15 are provided on an axial inner surface of the housing 17, and, further, the vane pressure inlet port 14 and the vane pressure outlet port 15 oppose each other with respect to the rotor axis A-A. While the inlet port 12 and outlet port 13 are designed as the input and output, respectively, for fluid with regards to the working chamber 5, the vane pressure inlet port 14 and the vane pressure outlet port 15 are ports designed for communicating (i.e., inputting and outputting) fluid to provide increased volume of fluid as part of an additional pumping mechanism, i.e., to add to the total displacement of the pump. For example, as shown in FIGS. 1 and 4 , in an embodiment, a number of vane ports 4 are provided in the rotor 1 at a proximal end (i.e., proximal to rotational axis A-A and/or central opening 23) of the vane mounting openings 22. Each vane port 4 is in communication with at least an associated vane mounting opening 22. Each vane port 4 also faces the axial inner surface(s) of the housing 17, preferably extending axially to the axial face of the rotor 1. Accordingly, each vane port 4 is configured to intake and/or discharge fluid from the vane pressure inlet port 14 and/or the vane pressure outlet port 15, depending on the positioning of the rotor 1 and the vane 2 in the associated vane mounting opening 22. In particular, each vane port 4 is a port that communicates to a space in an associated vane mounting opening 22 which is positioned behind a vane 2 therein (i.e., wherein behind is defined as being at a proximal end of the vane 2 which is closer to the rotational axis A—A and/or central opening 23, whereas a distal end of a vane 2 is defined as an end designed for engagement with the internal surface of the rotor receiving space of control slide 6). Such vane ports 4 may also be referred to as “undervane” ports by those skilled in the art and herein, as these ports 4 are positioned relatively below or under a vane positioned within a vane slot or a vane mounting opening when viewed radially (a radially inner under-the-vane port), as the distal end of the vane moves towards and/or into contact with the rotor receiving space / control slide 6. Each port 4 may intake and discharge fluid from its space.

Accordingly, in addition to use of pins or intermediate transfer members 3 eliminating the need for vane ring(s), fluid is configured to flow through the vane ports 4 and to the axial end face(s) of the rotor. Delivery of fluid in and through vane ports 4/undervane ports creates pumping mechanisms in each vane port 4 of a vane slot/opening 22 from the sliding motion of the vane 2 moving in and out of the vane receiving openings 22 as the rotor 1 rotates. This creates a second (inner) pump that behaves similarly to a piston pump, with positive pressure being generated by the vanes 2 that are being pressed inwardly via engagement with the slide 6 inner surface as the rotor rotates and negative pressure being generated by the opposite vane of each pair being extended outwardly (e.g., in the example of FIG. 1 , the vanes are pressed inwardly as they move from 12 to 6 o'clock, and the opposite vanes extend outwardly as they move from 6 to 12 o'clock). Thus, the vane ports 4 also create inlet and outlet ports in the rotor 1 for the fluid, thereby providing an extra volume that may be pumped by the rotor 1 and vanes 2. In accordance with an embodiment, the extra volume of fluid pumped through the undervane ports/vane ports 4 and provided on the axial end faces of the rotor 1 may be combined with the normal output from the working chamber 5 (i.e., the normal vane (outer) pump), to increase overall or total pump displacement. In another embodiment, the fluid directed in vane ports 4 may be used separately from the pressurized fluid from working chamber 5 as a second small displacement pump. That is, the fluid output from vane ports 4 may be separate from the output and displacement through the main/normal outlet of the pump, to provide fluid to another system and/or for another purpose.

In one embodiment, the vane pressure inlet port 14 may be arranged in a low-pressure region of the internal chamber of the housing 17. This low-pressure region is a region or side in which the vanes 2 are extending radially outwardly from the axis A-A (to the right of the 12-6 o'clock direction in FIG. 1 ), thereby creating a lower pressure (or negative pressure) for suction of fluid. This enables the vane pressure inlet port 14 to communicate with the vane port(s) 4 for at least one vane mounting opening 22 passing thereover, to thus enable the associated vane 2 in said vane mounting opening 22 to draw fluid into the vane port 4 and the vane mounting opening 22 via the vane pressure inlet port 14 as the vane 2 extends radially outwardly. Further, in one embodiment, the vane pressure outlet port 15 may be arranged in a high-pressure region of the internal chamber of the housing 17. The high-pressure region is a region or side in which the vanes 2 are retracting radially inwardly towards the axis A-A (to the left of the 12-6 o'clock direction in FIG. 1 ), thereby creating an increased displacement. This enables the vane pressure outlet port 15 to communicate with the vane port(s) 4 of at least one vane mounting opening 22 passing thereover, to thus enable the associated vane 2 retracting radially inwardly in said vane mounting opening 22 to eject fluid from the vane mounting opening 22 and vane port 4 via the vane pressure outlet port 15. Generally, such regions of a vane pump are understood by a person having ordinary skill in the art.

In an embodiment, the inlet port 12 and the outlet port 13 are on the axial inner surface of the housing 17. These inlet and outlet ports 12 and 13 may also be referred to as primary or main inlet and outlet ports, as they are responsible for the traditional displacement generated by the pump (in contrast with the smaller amount associated with vane pressure inlet and outlet 14, 15). As shown in FIG. 5 , in a bottom or underside view of the vane pump, in an embodiment, the vane pressure inlet port 14 may be adjacent to and radially inward of the inlet port 12, and the vane pressure outlet port 15 may be adjacent to and radially inwardly of the outlet port 13. In accordance with one particular exemplary embodiment, the axial inner surface of the housing 17 is provided by a porting plate 11 (see FIGS. 4 and 5 ) that is attached to the housing 17 of the pump. In one embodiment, the plate 11 closes off and seals an axial side of the internal chamber and seals against the rotor 1 and the control slide 6. That is, in an embodiment, the housing 17 may include a surrounding body which is flanked by the porting plate 11 connected to one side, e.g., its bottom, and a cover (not shown) that is connected to the opposite side, e.g., its top. Like the plate 11, the cover may close off and seal an opposite axial side of the internal chamber and seal against rotor 1 and control slide 6.

As depicted in FIG. 5 and better shown in the cross sectional view of FIG. 3 , in an embodiment, at least the vane pressure inlet port 14 and the vane pressure outlet port 15 extend through a thickness of the plate 11 in the axial direction of the rotor axis A-A. In one embodiment, the inlet port 12, the outlet port 13, the vane pressure inlet port 14, and the vane pressure outlet port 15 extend through a thickness of the plate 11 in the axial direction of the rotor axis A-A. However, such depictions are not intended to be limiting. That is, in accordance with an embodiment, the vane pressure inlet port 14 and the vane pressure outlet port 15 may be port holes (which may or may not be circular) that are provided in porting plate 11. In one embodiment, indentations may be provided on one axial side of the plate 11 (e.g., the axial side of the plate 11 that faces the rotor 1 and housing 17) to direct fluid to/from the vane pressure inlet port 14 and the vane pressure outlet port 15. Thus, the illustrations are only intended to be illustrative and not intended to be limiting. The shape of the vane pressure inlet port 14 and the vane pressure outlet port 15 as shown in the Figures is also not intended to be limiting.

While the principles of the disclosure have been made clear in the illustrative embodiments set forth above, it will be apparent to those skilled in the art that various modifications may be made to the structure, arrangement, proportion, elements, materials, and components used in the practice of the disclosure.

It will thus be seen that the features of this disclosure have been fully and effectively accomplished. It will be realized, however, that the foregoing preferred specific embodiments have been shown and described for the purpose of illustrating the functional and structural principles of this disclosure and are subject to change without departure from such principles. Therefore, this disclosure includes all modifications encompassed within the spirit and scope of the following claims. 

What is claimed is:
 1. A vane pump comprising: a housing comprising an internal chamber; an inlet port; an outlet port; a rotor rotatably mounted in the internal chamber for rotation about a rotor axis, the rotor having a plurality of vane mounting openings and a plurality of vanes mounted in and extending radially from the vane mounting openings, the vanes being slidable radially in the vane mounting openings; a control slide mounted in said internal chamber, the control slide having an internal surface defining a rotor receiving space, wherein the rotor receiving space is in communication with the inlet and outlet ports and the rotor is received in the rotor receiving space with the vanes slidably engaging the internal surface of the control slide such that rotating the rotor generates a pressure differential between the inlet and outlet ports to draw fluid in through the inlet port and output the fluid out through the outlet port; wherein the plurality of vane mounting openings are arranged in pairs of vane mounting openings that are diametrically opposed to one another with respect to the rotor axis and wherein the plurality of vanes include pairs of vanes that are diametrically opposed to one another with respect to the rotor axis, wherein the vanes in each said pair have an intermediate transfer member extending therebetween that shifts with one vane of each said pair retracting radially inwardly by engagement with the internal surface of the rotor receiving space for extension of the opposing vane of each said pair radially outwardly toward the internal surface of the rotor receiving space.
 2. The vane pump of claim 1, wherein the intermediate transfer member for each pair of vanes is a pin provided between the vanes of the pair.
 3. The vane pump of claim 2, wherein each pin is cylindrical.
 4. The vane pump of claim 1, wherein the rotor includes a rotor body with a central opening and the vane mounting openings extend radially inwardly from an outer radial surface of the rotor body, the rotor body further comprising a plurality of receiving bores each extending from a respective vane mounting opening to the central opening of the rotor body, the receiving bores for each pair of vane mounting openings being radially aligned with one another and having the intermediate transfer member for the associated pair of vanes slidably received therein, each radially aligned pair of receiving bores being spaced axially with respect to the rotor axis from each other pair of radially aligned pair of receiving bores such that the intermediate transfer members cross over one another in the central opening of the rotor body.
 5. The vane pump of claim 4, wherein the intermediate transfer member for each pair of vanes is a pin provided between the vanes of the pair.
 6. The vane pump of claim 5, wherein each pin and each receiving bore is cylindrical.
 7. The vane pump of claim 1, further comprising a vane pressure inlet port and a vane pressure outlet port each on an axial inner surface of the housing, the vane pressure inlet port and the vane pressure outlet port opposing each other with respect to the rotor axis, wherein the rotor includes a plurality of vane ports in communication with an associated vane mounting opening and facing the axial inner surface of the housing, the vane pressure inlet port being arranged in a low-pressure region of the internal chamber in which the vanes are extending radially outwardly to enable the vane pressure inlet port to communicate with the vane port for at least one vane mounting opening passing thereover to enable the associated vane extending radially outwardly to draw fluid into said vane mounting opening, the vane pressure outlet port being arranged in a high-pressure region of the internal chamber in which the vanes are retracting radially inwardly to enable the vane pressure outlet port to communicate with the vane port of at least one vane mounting opening passing thereover to enable the associated vane retracting radially inwardly to eject fluid through said vane mounting opening.
 8. The vane pump of claim 7, wherein the inlet port and the outlet port are on the axial inner surface of the housing, the vane pressure inlet port being adjacent to and radially inward of the inlet port and the vane pressure outlet port being adjacent to and radially inwardly of the outlet port.
 9. The vane pump of claim 8, wherein the axial inner surface of the housing is provided by a plate attached to the housing of the pump, the plate closing off and sealing an axial side of the internal chamber and sealing against the rotor and the control slide.
 10. The vane pump of claim 9, wherein the inlet port, the outlet port, the vane pressure inlet port, and the vane pressure outlet port extend through a thickness of the plate in the axial direction of the rotor axis.
 11. The vane pump of claim 1, wherein the control slide is movable in (a) a displacement increasing direction to increase an eccentricity between the rotor axis and the rotor receiving space for increasing the pressure differential between the inlet and the outlet, and (b) a displacement decreasing direction to decrease the eccentricity between the rotor axis and the rotor receiving space for decreasing the pressure differential between the inlet and the outlet. 